Fang Mei-Ling, Wu Ching-Yi, Chou Ming-Shean
a Institute of Environmental Engineering , National Sun Yat-sen University , Kaohsiung , Taiwan , Republic of China.
J Air Waste Manag Assoc. 2018 Jul;68(7):755-762. doi: 10.1080/10962247.2018.1461710. Epub 2018 May 22.
Some metal etching operations emit limited flow rates of waste gases with reddish-brown NO fume, which may cause visual and acidic-odor complaints, as well as negative health effects. In this study, tests were performed by passing caustic-treated waste gases vented from Al-etching operations through columns packed either with virgin or regenerated granular activated carbon (GAC) to test their adsorptive conversion performance of NO in the gases. The gases contained 5-55 ppm NO and acetic and nitric acids of below 3 ppm. Exhausted carbon was regenerated by scrubbing it with caustic solution and water, and dried for further adsorption tests. Results indicate that with an (empty bed residence time (EBRT) of 0.15 sec for the gas through the GAC-packed space, around 60% of the influent NO of 54 ppm could be removed, and 47% of the removed NO was converted by and desorbed from the carbon as NO. GAC used in the present study could be regenerated at least twice to restore its capacity for NO adsorption. Within EBRTs of 0.076-0.18 sec, the adsorptive conversion capacity was linearly varied with EBRT. In practice, with an EBRT of 0.20 sec, a conversion capacity of 0.80 kg NO (kg GAC) with an influent NO of 40 ppm can be used as a basis for system design.
Some metal etching operations emit waste gases with reddish-brown (yellow when diluted) NO fume which may cause visual and acidic-odor complaints, as well as negative health effects. This study provides a simple process for the adsorptive conversion of NO in caustic-treated waste gases vented from metal-etching operations through a GAC column. With an EBRT of 0.20 sec, a conversion capacity of 0.80 kg NO (kg GAC) with an influent NO of 40 ppm can be used as a basis for system design. Saturated GAC can be regenerated at least twice by simply scrubbing it with aqueous caustic solution.
一些金属蚀刻操作会排放出流量有限的废气，其中含有红棕色的一氧化氮烟雾，这可能会引发视觉和酸臭味方面的投诉，以及对健康产生负面影响。在本研究中，通过使铝蚀刻操作排出的经过苛性处理的废气通过填充有原始或再生颗粒活性炭（GAC）的柱子来进行测试，以检验它们对气体中一氧化氮的吸附转化性能。这些气体含有5 - 55 ppm的一氧化氮以及浓度低于3 ppm的乙酸和硝酸。耗尽的碳通过用苛性溶液和水洗涤进行再生，并干燥以进行进一步的吸附测试。结果表明，对于气体通过填充GAC的空间的空床停留时间（EBRT）为0.15秒时，54 ppm的进水一氧化氮中约60%可以被去除，并且被去除的一氧化氮中有47%被碳转化并以一氧化氮的形式解吸出来。本研究中使用的GAC可以至少再生两次以恢复其对一氧化氮的吸附能力。在0.076 - 0.18秒的EBRT范围内，吸附转化能力随EBRT呈线性变化。在实际应用中，对于进水一氧化氮为40 ppm且EBRT为0.20秒时，0.80千克一氧化氮/（千克GAC）的转化能力可作为系统设计的依据。
一些金属蚀刻操作会排放出带有红棕色（稀释后为黄色）一氧化氮烟雾的废气，这可能会引发视觉和酸臭味方面的投诉，以及对健康产生负面影响。本研究提供了一个简单的过程，用于通过GAC柱对金属蚀刻操作排出的经过苛性处理的废气中的一氧化氮进行吸附转化。对于进水一氧化氮为40 ppm且EBRT为0.20秒时，0.80千克一氧化氮/（千克GAC）的转化能力可作为系统设计的依据。饱和的GAC通过简单地用苛性水溶液洗涤至少可以再生两次。
